Despite the clear potential for endothelial function improvement and cardiovascular risk reduction, statin therapy has never been evaluated in survivors of childhood cancer. Although statins have been well-studied in other patient populations at risk for cardiovascular disease, there is strong justification for evaluation in cancer survivors since the mechanisms responsible for the vascular problems in these individuals (treatment-induced vascular toxicity) differ from traditional atherosclerosis. Therefore, the objective of the current study is to assess the ability of statin therapy to improve endothelial function, arterial stiffness, and arterial thickening in young adult survivors of childhood cancer. The focus of the study will be on survivors of hematologic malignancies, acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL), since the former has been shown to be associated with endothelial impairments and both cancers share common treatment exposures (chemotherapy and radiation), which is likely the primary factor responsible for endothelial dysfunction in these individuals.